Scarus niger

Reproduction

The dusky parrotfish is a protogynous hermaphrodite.The dominant female in a group with only females may turn into a male; such males are called secondary males. Male and female fish form pair during breeding. After breeding, the gonads drastically reduce in size.^[4]

Feeding behavior

The dusky parrotfish feeds primarily on benthic algae growing on hard substrates and dead coral. Unlike some larger parrotfish species, it typically does not feed on live coral. This small parrotfish species has a very high feeding rate compared to other parrotfish species, biting more times in a given period of time. Nonetheless, its small bite volume means it contributes far less bio-erosion compared larger parrotfish species. It does not follow any set feeding pattern, but it tends to feed more in the morning and afternoon rather than at midday and sundown.^[5]

Denser coral patches that provide more cover for the fish leads to a decrease in the foraging range, as well as denser populations. In comparison with other species of parrotfishes, the dusky parrotfish tends to be less aggressive to other parrotfish species and will decrease its foraging range when it is in an environment with a high parrotfish density. As a result, in such environments, other parrotfish species compete with S. niger instead of offering benefits from group foraging, such as reductions in predation risks.^[6]